Method and apparatus for vaporizing material



May 14, 1968 E L. OBERTO 3,382,603

METHOD AND APPARATUS FOR VAPORIZING MATERIAL Filed June 30, 1966Internal Combustion Inventor Edwin. L. Oberto E lama-K m WMW fl-HornegsUnited States Patent Delaware Filed June 30, 1966, Ser. No. 561,938 20Claims. (Cl. 43-129) The present invention relates to a method andapparatus for producing an aerosol from a material such as aninsecticide or a herbicide, and the following disclosure thereof isoffered for public dissemination upon the grant of a. patent therefor.

One common procedure for vaporizing insecticides, etc. is to provide asolution of the material in a carrier. The solution is then sprayed andheated to produce an aerosol. The present invention involves theliquidizing of the material by heat without the use of a carrier. Thusby dispensing with the necessity for formulation there is a costadvantage in producing insecticide, etc., dispersions by use of thepresent invention. Furthermore, the use of the present invention is notlimited to dispensing materials that are soluble in a suitable vehicle.Also, it eliminates the dange or combustion of the vaporized vehicle,which is an oil or other volatile solvent in many presently employedformulations.

The present invention employs an internal combustion engine as a sourceof heat, thus it is capable of being employed in locations in whichelectricity is not available. Since the heat is derived from the exhaustsystem, there is the advantage of lack of moving parts as compared todevices driven by an internal combustion engine, which devices do workin order to obtain heat.

An important feature of the invention is the manner of controlling theheat employed for useful purposes, e.g., of controlling the temperaturefor melting the solid material. This is important since some materialsare deleteriously affected by excess heat. While engine exhaust systemspreviously have been used as a source of heat there has been no adequatemeans in the prior art for controlling the amount of heat thus employed,to the best of my knowledge.

Further objects and advantages will be apparent from the followingdescription taken in conjunction with the drawings in which:

FIGURE 1 is a diagrammatic illustration of an embodiment of the presentinvention; and

FIGURE 2 is a modification of the embodiment of FIGURE 1.

Although the following disclosure offered for public dissemination isdetailed to ensure adequacy and aid understanding, this is not intendedto prejudice that purpose of a patent which is to cover each newinventive concept therein no matter how others may later disguise it byvariations in form or additions or further improvements. The claims atthe end hereof are intended as the chief aid toward this purpose; as itis these that meet the requirement of pointing out the parts,improvements, or combinations in which the inventive concepts are found.

In the present invention heat is transferred from the engine exhaust tothe material which is liquified through a heat transfer medium. Theliquified material is then carried into the engine exhaust where it isfurther heated and vaporized. The discharge of the engine exhaustprovides the force to deliver the aerosol at the area of application. Tocontrol the heat, a reservoir of the heat transfer medium is maintainedwith ambient air conditions being employed to stabilize the temperatureof the medium in the reservoir. A second body of the heat transfermedium is maintained in heat exchange relationship with the engineexhaust and in heat exchange relationship with the material. Cooledmedium from the reservoir is added to the body of medium that is in heatexchange relationship at a rate which will maintain the temperature ofthe latter at the desired level. Normally this is done by means of acontinuous circulation of the medium between the heat exchange bodythereof and the reservoir, with temperature control being achieved bymeans of control of the amount of that circulation.

By use of this method one can vaporize herbicides, such as atrazine,dicamba and trifluralin from the solid state. By varying the rate ofcirculation of the medium one can achieve a melting temperature suitablefor the material being employed, even though the materials have widelydifferent melting ranges. For example, trifluralin has a meltingtemperature of 46-47 degrees Centigrade, while atrazine has a meltingtemperature of 173-175 degrees centigrade. One can vaporize aninsecticide such as heptachlor which has a melting temperature of -96degrees centigrade.

FIGURE 1 illustrates an internal combustion engine 10, having an exhaustpipe 11. The exhaust pipe defines a venturi 12 and has a dischargeopening 13. Pipe 11 extends through a container 15 for holding a heatexchange medium 16. The walls of container 15 are insulated, asillustrated at 17, in order to achieve a more uniform temperature in thecontainer and prevent heat losses therefrom. The container is providedwith a removable lid 18. Within the container is a melting tank 19 inwhich is received the material 20 to be vaporized. In the usual casethat material will be in solid form before heat is applied in accordancewith the present invention.

Two pipes, 22 and 23 respectively, connect container 15 to a reservoir24. Reservoir 24 is exposed to ambient air conditions so as to cool themedium 16 therein. If additional heat transfer out of the reservoir isrequired, means such as fins 25 are employed in the manner of aradiator. The amount of heat transfer out of reservoir 24, and thequantity of medium 16 in reservoir 24 as compared to the amount ofmedium 16 in container 15, should be such that the medium in thereservoir will have a comparatively stable temperature (substantiallybelow the temperature of the medium in container 15) under normaloperating conditions. A pump 26 and a regulating valve 27 are providedin pipe 23 to control the flow between the reservoir and the container.As indicated by dot-dash line 28, pump 26 is driven by engine 10.However, in some instances the pump 26 can be dispensed with and thecirculation between the reservoir and the container achieved by gravity.

A temperature responsive bulb or sensing element 30 is mounted incontainer 15 in heat exchange relationship with the medium 16 and withtank 19 (and thus in heat exchange relationship with the material 20).In some embodiments the sensing element 30 will only be in temperatureexchange relationship with the medium 16 and in other embodiments onlywith the tank (and contents) 19. As indicated by dot-dash line 31, thebulb is employed to automatically control the setting of valve 27 andthus the flow through pipe 23. It is also employed to automaticallycontrol the discharge of pump 26, as indicated by line 31a. Aspreviously explained, the point is to control the circulation betweenthe reservoir and the container so as to maintain the temperature of themedium 16 in the container 15 (and thus that of the material 20) at apredetermined level. This level may be preset by hand wheel 32 on valve27. In some embodiments this automatic control over the circulation, tocontrol the temperature, is achieved solely by pump 26, while in otherembodiments it will be achieved solely by means of valve 27.

A conduit 34 has one end 35 in communication with the interior of tank19, and the other end 36 positioned in the low ressure area achieved inthe exhaust pipe 11 by venturi 12. A valve 37 is mounted in conduit 34to control the rate of flow therethrough. The setting of valve 37 isachieved by a hand Wheel 38.

The rate of flow of the medium 16 between reservoir 24 and tank 15 isadjusted so that the temperature of the medium 16 in the container 15will be suitable for melting the material 20 in tank 19. The meltedmaterial is drawn through pipe 34 and discharged into the exhaust of theengine at conduit end 36. It will be noted that a portion of pipe 34upstream of end 36 extends down through the exhaust pipe 11 in heatexchange relationship with the exhaust. The extent of this heat exchangerelationship (i.e., length of pipe so exposed to additional heat) can besufficient to supply an amount of heat to the material 20 so that thematerial is about at its vaporization point when it reaches end 36.Vaporization should not occur before end 36 is reached as this willcause a vapor lock, Of course, the vaporized material is discharged outof end 13 of the exhaust pipe, which end is positioned so as todischarge the vaporized material, or aerosol, where desired.

In the illustrated embodiment the flow through conduit 34 is achievedboth by gravity and by the vacuum provided by venturi 12. In someembodiments either one or the other of these two procedures forachieving the flow of material can be employed alone. Thus, for example,venturi 12 could be eliminated and it would even be possible to havedischarge end 36 of the conduit downstream from the discharge end 13 ofthe exhaust pipe, provided that pressure atomization is employed. Thevaporized material still would be within the exhaust and would bedispersed by the engine exhaust. In the embodiments disclosedatomization is achieved through the use of the venturi.

In FIGURE 2 there is no additional heating of the material in pipe 34 asoccurs in pipe 34 in FIGURE 1. Pipe 34 has a small opening 36 directlyat the wall of the venturi 12.

It should be pointed out that the stabilization of the externaltemperature of exhaust pipe 11, will also have some stabilizing effectupon the amount of heat of the exhaust in the pipe. It is this latterheat that is employed in the final vaporization of the liquid material.

I claim:

1. A method of producing an aerosol by using an internal combustionengine to vaporize a solid material comprising the steps of:transferring heat from the exhaust of said engine to said material toliquify the same; introducing said material after liquification intosaid exhaust and vaporizing the same; and releasing said exhaust to-Ward the object to be treated.

2. The method of claim 1, wherein after said material has been liquifiedand immediately prior to its introduction, additional heat istransferred to the material from said exhaust.

3. The method of claim 1, wherein the heat is transferred from theexhaust to the material through a liquid transfer medium, and thetemperature of said medium is selectively controlled.

4. The method of claim 3, wherein the temperature control of said mediumis obtained by maintaining a reservoir of said medium, cooling themedium in said reservoir by exposure to ambient conditions, maintaininga body of heated medium in heat transfer relationship between saidexhaust and said material, transferring the heated medium from said bodyto said reservoir at a controlled rate, and replacing the transferredmedium by 4 moving cooled medium from the reservoir to the body thereof.

5. The method of claim 4, wherein after said material has been liquifiedand immediately prior to its introduction, additional heat istransferred to the material from said exhaust.

6. The method of claim 4, wherein the material is selected from thegroup consisting of herbicide and insecticide.

7. The method of claim 1, wherein said material is atomized andintroduced into said exhaust without first introducing additional heatinto the material beyond that employed to liquify the same.

8. An apparatus for discharging a vaporized material and using aninternal combustion engine and the material, said apparatus including: aheating tank for holdig said material; a liquid heat transfer medium inheat transfer relationship with said tank; an engine exhaust pipe inheat transfer relationship with said medium; and a conduit having oneend positioned to pickup the liquid material from the tank and the otherend positioned to discharge the material into said exhaust; whereby heatwill be transferred through said medium from said exhaust to saidmaterial to heat the same, and the material conducted to said exhaustwill be vaporized by said exhaust.

9. An apparatus as set forth in claim 8, and including container meansto hold a body of said medium about said tank and about said exhaustpipe; reservoir means for said medium and having two pipes connected tosaid container means; and flow control means connected to said reservoirmeans to control the flow of the medium between the reservoir means andthe container means.

10. An apparatus as set forth in claim 9, wherein said flow controlmeans is temperature responsive.

11. An apparatus as set forth in claim 10, wherein said flow controlmeans has a temperature sensing member in heat transfer relationshipwith said medium.

12. An apparatus as set forth in claim 10, wherein said flow controlmeans has a temperature sensing member in heat transfer relationshipwith the material in said tank.

13. An apparatus as set forth in claim 9, wherein said exhaust pipeextends through said container means.

14. An apparatus as set forth in claim 9, wherein said flow controlmeans includes a pump operatively connected to said engine to be driventhereby for pumping the medium between said reservoir means and saidcontainer means.

15. An apparatus as set forth in claim 14, wherein said flow controlmeans includes a valve.

16.- An apparatus as set forth in claim 8, wherein said exhaust pipeincludes a venturi defining a relatively low pressure area in saidexhaust pipe in relation to the pressure elsewhere in the pipe, saidother end being positioned in said area.

17. An apparatus as set forth in claim 16, wherein said conduit extendsthrough the interior of said pipe upstream of said area.

18. An apparatus as set forth in claim 16, including adjustable flowcontrol means in said conduit.

19. An apparatus as set forth in claim 8, wherein a portion of saidconduit is in heat transfer relationship with said exhaust.

20. An apparatus as set forth in claim 8, and including a containerabout said tank, said exhaust pipe extending through said container,said exhaust pipe including a venturi defining a relatively low pressurearea in said pipe in relation to the pressure elsewhere in the pipe,said other end being positioned in said area, said conduit extendingthrough the interior of said pipe upstream of said area, adjustable flowcontrol means in said conduit, reservoir means for said medium andhaving two pipes connected to said container means; and flow controlmeans connected to said reservoir means to control the flow of themedium between the reservoir means and the References Cited UNITEDSTATES PATENTS Hammond et a1 43-125 Metzger et a1. 43-125 Rupprecht23-227 Loy et a1. 43-129 6 10/1953 Loy et a1. 252-359 8/1959 Cragg eta1. 239-129 1/1963 Johnson et a1. 43-129 9/1965 Tenney 252-359 4/ 1966Durr et a1. 252-359 FOREIGN PATENTS 7/1951 Great Britain. 8/1962 GreatBritain.

ALDRICH F. MEDBERY, Primary Examiner.

1. A METHOD OF PRODUCING AN AEROSOL BY USING AN INTERNAL COMBUSTIONENGINE TO VAPORIZE A SOLID MATERIAL COMPRISING THE STEPS OF:TRANSFERRING HEAT FROM THE EXHAUST OF SAID ENGINE TO SAID MATERIAL TOLIQUIFY THE SAME; INTRODUCING SAID MATERIAL AFTER LIQUIFICATION INTOSAID EXHAUST AND VAPORIZING THE SAME; AND RELEASING SAID EXHAUST TOWARDTHE OBJECT TO BE TREATED.